1. Field of the Invention
The present invention relates to a device for supplying electric current to a plurality of modules clustered in an electronic rack.
2. Discussion of the Background
It applies in particular, but not exclusively, to the electronic equipment carried on board aerodynes which are supplied from a DC electric current distribution network. It turns out that the DC voltage provided by this network is greatly perturbed, this being prejudicial in respect of the electronic equipment which might be supplied via such a voltage.
These perturbations originate firstly from the fact that the energy sources which supply this network are not unique. Indeed, when the engines of the aerodyne are stopped, the network is supplied from batteries, but when the engines are running, the network is supplied from electrical generators coupled to the engines. Moreover, an aerodyne in flight may be subject to strong electromagnetic perturbations, and in particular lightning, and this may give rise to considerable overvoltages in the electrical network or conversely brownouts.
Likewise, the variations in the load on this network and in the consumption by the equipment supplied therefrom, as well as the regulating transients of the generators, give rise to considerable momentary variations in voltage. Thus, for a nominal voltage of 28 volts, voltage variations possibly reaching 12 to 48 volts have been noted. Moreover, the overvoltages engendered by lightning may be much more considerable.
It is therefore necessary to provide a voltage regulating device in regard to each item of equipment carried, capable of withstanding and dealing with such voltage variations.
Moreover, equipment carried on board aerodynes is evolving towards an evermore modular and evermore integrated architecture comprising racks or cabinets in which are clustered a multiplicity of modules having needs in terms of supply voltage which vary from one module to another.
Each module has therefore been furnished with a supply device comprising all the necessary DC voltage conversion and regulating means. Now, the components allowing the regulating of such voltage variations are relatively voluminous and costly. It follows that, applied to a multiplicity of modules, this approach is costly and leads to the size of each module being considerably increased, and to its reliability being reduced since the module must then withstand large voltage variations.
The purpose of the present invention is to overcome these drawbacks. To this end, it proposes a supply device for supplying DC electric current to a plurality of consumer electronic modules, on the basis of a DC voltage exhibiting a wide voltage variation range, this device comprising voltage regulating means and voltage conversion means.
According to the invention, this device is characterized in that it comprises a primary supply module comprising voltage preregulating means able to step up or step down the voltage in order to provide the modules with a preregulated voltage exhibiting a small voltage variation range and, in regard to each module, voltage conversion means providing voltages adapted to the needs of the module.
By virtue of these arrangements, the costly and bulky power regulating components are clustered in a single module, while the converters integrated into each consumer module are inexpensive and compact, given that they are required to deal only with a voltage subject to small variations.
Thus, for example, when the voltage to be regulated varies between 12 and 48 volts around a nominal voltage of 28 volts, the primary supply module according to the invention makes it possible to obtain, as output, a preregulated voltage which varies at most between 18 and 32 volts. Such a range of variation is perfectly acceptable to cheap DC voltage converters available on the market.
Moreover, the wiring necessary to supply each consumer module from the supply module comprises just two electrical leads, each module remaining autonomous as regards the production of the voltages which it needs. Thus, this avoids the requirement to provide specific wiring to convey each necessary voltage between a common supply module and the consumer modules.
This solution therefore makes it possible to simplify the wiring, and thus to reduce the costs considerably.
Advantageously, the means of voltage conversion in regard to each module comprise galvanic isolation means making it possible to circumvent the perturbations which could occur on the preregulated current distribution line between the primary supply module and the consumer modules.
According to one particular feature of the invention, each consumer module is supplied by means of one respective line per primary supply module which comprises, at each supply line feed, automatic outage means for protection against short-circuits.
This arrangement makes it possible to obtain great security of operation, each module being supplied via an independent line and being able to be powered-up selectively by the primary supply module should there be a short-circuit in regard to the module of the supply line.